Ke$ha has co-written a track for Britney Spears' forthcoming album, 'Femme Fatale'.

The glitter loving 'We R Who We R' pop star has previously penned songs for The Veronicas, sang the female vocals on Flo Rida's 'Right Round' and also performed backing vocals on Spears' own 'Lace and Leather' so her credentials as both a writer and musician are solid. 

The song she has written for Spears' new record is called 'Till The World Ends', and she created it with Dr. Luke and Max Martin who have both worked extensively on 'Femme Fatale' along with Spears' older albums. Ke$ha said of the track:

"That song is me imagining her and any female musician touring the world,"

"You know, when you got out, and you're having an amazing, magical night and you don't want to go to sleep and you want it to last until the world ends."

Watch Ke$ha jump out of a plane during her recent trip to Australia here: